Oxygen – everything we know and love depends on the stuff. The abundance of free and molecular oxygen throughout Earth is a major defining feature of our planet, one that distinguishes it from the rest of the solar system.
Everyone knows oxygen is pretty important. We need it to breathe. We need it to exist at all. But would it really matter if oxygen disappeared from the universe for, say, 5 seconds? Couldn’t the universe hold its breath for that long?
Definitely not – oxygen is an absolutely vital force, responsible for sustaining not only the entire biosphere but the stability of the lithosphere and atmosphere, as well. Without the big O, all fires would be extinguished. Buildings would turn to dust, and the oceans would simply evaporate. And that’s not all; read on to glimpse the horrors of an anoxic world and universe.
<h2>’Life’ Without Oxygen</h2>
Without oxygen, Earth would be a shadow of its former self. First, a mass extinction of lifeforms would sweep the planet. All but a few multicellular organisms would die instantly. Humans would experience mass neuronal death and collapse of brain function, blood flow, metabolism, and respiration. Fluids would boil away; bodies would turn to dust.
All water would instantly be hydrogen gas and rise to the upper reaches of the atmosphere. Around the world, extremophiles would celebrate. We’d be left with sulfur-reducing bacteria, methanogens, viruses. Life would be simple and slow. Twenty years ago, we might have assumed no life would prevail, but science has since uncovered organisms that can survive without oxygen. However, it’s safe to assume speciation would essentially be rolled back to ground zero.
The least amount of oxygen is found in the atmosphere, so it would experience the least change, though that’s not saying much. With oxygen on vacation, the ozone layer would be no more, leaving us exposed to carcinogenic UV radiation. There would be an overall reduction of particles in the air, which would cause the sky to lose its blue hue and turn carbon-black. Every region would lose cabin pressure.
The lithosphere is the largest source of oxygen, so familiar mineral profiles would be wiped out. Without silicates, the crust and mantle would collapse in on themselves. The removal of trace oxygen in the core could reduce convection in the liquid outer core and weaken Earth’s magnetic field, exposing the planet to a huge burst of solar irradiation. In that case, solar winds would rip away the remaining atmosphere.
<h2 class=”p1″>Evolution in Reverse</h2>
What if oxygen did not return after five seconds? The destruction of Earth as we know it would greatly accelerate as the species left behind – mainly viruses, single-celled microbes, and <a href=”https://news.nationalgeographic.com/news/2010/04/100416-oxygen-free-complex-animals-mediterranean/”>a few specially adapted multicellular organisms</a> – moved to consume the next best thing. Where the seas used to be, toxic hydrogen sulfide would envelop barren landscapes. Soon, everything would smell of rotten eggs, and most rocks would darken like the sky overhead.
Volcanic eruptions would become epidemic, raining ash, acid and fumes on the land and creating a gaseous buffer that would make Earth a hot, poison-filled super-greenhouse. Continual eruptions would remake the planet, building up new land masses and derailing the global climate.
The fact that we have an oxygen-rich atmosphere is incredibly unusual. Actually, Earth’s earliest atmosphere contained no oxygen at all. And for most of the planet’s history, oxygen levels have been quite restricted. Less than a billion years ago, things began to change in favor of the friendly element, and life bloomed. Losing our oxygen would feel a lot like undoing a billion years of geologic progress. It would be like evolution in reverse.